I pray that from His glorious, unlimited resources He will empower you with inner strength through His Spirit. (Ephesians 3:16 NLT)
The strength of the Lord's people is none other than the strength of the Holy Spirit in the inward man. Right at the very center of the being, deeper than thought or reason, deeper than emotion or feeling, deeper than all that which comprises the more outward man which, under given circumstances, may prove weak and incapable of standing up to the situation. In the variations of our soul life, the changes of our moods, our ideas, our attitudes, our feelings, our minds; deeper down there is that strength which does not let us go. That is the true nature of spirituality.
It is not the tremendously forceful conviction of our intellects or the mighty power of our wills. When these cannot stand up to conditions of intense spiritual antagonism, opposition or perplexity, there is that more inward thing, right in the inward man, which is of God – the Holy Spirit: “Strengthened with might by His Spirit into the inward man.”
Test that out and the result is that when the mind is bewildered by the perplexity of a situation, and the arguments are all in the direction that a mistake has been made, a wrong course has been taken, everything is false – when all the feelings are churned up, disturbed, anxious, fearful, or when there are no feelings at all, they are simply petrified by the position – when circumstances are all arguing in the opposite direction of that which we, in the purest moments of our fellowship with God determined upon.
The world around us – and very closely around us, even within the sphere of our own natural life, our own soul life – is an inexplicable mystery. Then spirituality is proved by that inward strength which abides: that standing when you cannot go forward; that holding when you can do nothing; that remaining when all the forces are seeking to sweep you off your feet. That represents a measure of spirituality. That is the true nature of the child of God.
The opposite is to be carried away by argument, reasoning, appearance, circumstance, and all such things. That proves a lack of true spirituality. In a sentence, true spirituality is not to live on the outside; it is to live with God right down deep in the inner part of your own being, where He, the Spirit, is.
By T. Austin-Sparks from: Filled Unto All the Fullness of God - Chapter 11